put the stack in bss to save space on disk

[netwatch.git] / grubload / multiboot_c.c

diff --git a/grubload/multiboot_c.c b/grubload/multiboot_c.c
index 990ffc65aecc045c0e45bab077da799b862d5812..890a003471db280f15a6941821a9d2c04e81b265 100644 (file)
--- a/grubload/multiboot_c.c
+++ b/grubload/multiboot_c.c
@@ -1,5 +1,8 @@
 #include "console.h"
 #include <io.h>
+#include <smram.h>
+
+#define INFO_SIGNATURE 0x5754454E
 
 extern char _binary_realmode_bin_start[];
 extern int _binary_realmode_bin_size;
@@ -22,8 +25,23 @@ struct mod_info
        void *reserved;
 };
 
-void c_start(unsigned int magic, struct mb_info *wee)
+struct info_section
+{
+       unsigned int signature;
+       void (*firstrun)();
+};
+
+void panic(const char *msg)
 {
+       puts("PANIC: ");
+       puts(msg);
+       puts("\nSystem halted\n");
+       while(1) asm("hlt");
+}
+
+void c_start(unsigned int magic, struct mb_info *mbinfo)
+{
+       struct mod_info *mods = mbinfo->mods;
        unsigned short *grubptr = (unsigned short *)0x7CFE;
        unsigned char smramc;
        int i;
@@ -34,24 +52,18 @@ void c_start(unsigned int magic, struct mb_info *wee)
        puts("NetWatch loader\n");
        
        if (magic != 0x2BADB002)
-       {
-               puts("Bootloader was not multiboot compliant; cannot continue.\n");
-               while(1) asm("hlt");
-       }
+               panic("Bootloader was not multiboot compliant; cannot continue.");
        
-       for (i = 0; i < wee->mod_cnt; i++)
+       for (i = 0; i < mbinfo->mod_cnt; i++)
        {
                puts("Module found:\n");
-               puts("  Start: "); puthex(wee->mods[i].mod_start); puts("\n");
-               puts("  Size: "); puthex(wee->mods[i].mod_end - wee->mods[i].mod_start); puts("\n");
-               puts("  Name: "); puts(wee->mods[i].mod_string); puts("\n");
+               puts("  Start: "); puthex(mods[i].mod_start); puts("\n");
+               puts("  Size: "); puthex(mods[i].mod_end - mods[i].mod_start); puts("\n");
+               puts("  Name: "); puts(mods[i].mod_string); puts("\n");
        }
 
-       if (wee->mod_cnt != 1)
-       {
-               puts("Expected exactly one module; cannot continue.\n");
-               while(1) asm("hlt");
-       }
+       if (mbinfo->mod_cnt != 1)
+               panic("Expected exactly one module; cannot continue.");
 
        puts("Current USB state is: "); puthex(pci_read16(0, 31, 2, 0xC0)); puts(" "); puthex(pci_read16(0, 31, 4, 0xC0)); puts("\n");
        puts("Current SMI state is: "); puthex(inl(0x830)); puts("\n");
@@ -64,12 +76,26 @@ void c_start(unsigned int magic, struct mb_info *wee)
        pci_write16(0, 31, 2, 0xC0, 0);
        pci_write16(0, 31, 4, 0xC0, pci_read16(0, 31, 4, 0xC0));
        pci_write16(0, 31, 4, 0xC0, 0);
-       smramc = pci_read8(0, 0, 0, 0x70);
-       pci_write8(0, 0, 0, 0x70, (smramc & 0xF0) | 0x04);
-       load_elf(wee->mods[0].mod_start, wee->mods[0].mod_end - wee->mods[0].mod_start);
-       pci_write8(0, 0, 0, 0x70, smramc);
-       outb(0x830, inb(0x830) | 0x41); /* turn on the SMIs we want */
-       
+
+
+       /* Open the SMRAM aperture and load our ELF. */
+       smram_state_t old_smramc = smram_save_state();
+
+       if (smram_aseg_set_state(SMRAM_ASEG_OPEN) != 0)
+               panic("Opening SMRAM failed; cannot load ELF.");
+
+       load_elf(mods[0].mod_start, mods[0].mod_end - mods[0].mod_start);
+
+       struct info_section * info = (struct info_section *)0x10000;
+       if (info->signature != INFO_SIGNATURE)
+       {
+               smram_restore_state(old_smramc);                /* Restore so that video ram is touchable again. */
+               panic("Info section signature mismatch.");
+       }
+
+       info->firstrun();
+       smram_restore_state(old_smramc);
+
        puts("Waiting for a bit before returning to real mode...");
        for (i=0; i<0x500000; i++)
        {